The field of the invention relates generally to aircraft gas turbine propulsion systems, and more particularly to a system and method for operating a thrust reverser for a turbofan propulsion system.
At least some known turbofan engines include a fan assembly, a core gas turbine engine enclosed in an annular core cowl, and a fan nacelle that surrounds a portion of the core gas turbine engine. The fan nacelle is spaced radially outward from the annular core cowl such that the core cowl and fan nacelle form a fan nozzle duct having a discharge area.
At least some known turbofan propulsion systems include a thrust reverser assembly. At least some known thrust reverser assemblies include a first fixed cowl, a second cowl that is axially translatable with respect to the first cowl, and a third cowl that is axially translatable with respect to the second cowl. More specifically, in some known thrust reverser assemblies, a first actuator is coupled to the second and third cowls and is actuated to reposition the second cowl with respect to the first cowl. In addition, a second actuator is coupled to the third cowl and is actuated to reposition the third cowl with respect to the second cowl. During operation of at least some known turbofan engines, the second cowl is repositioned to channel at least a portion of airflow discharged from the fan nozzle duct through the thrust reverser actuation system to facilitate adjusting a direction of thrust discharged from the turbofan engine. The third cowl is repositioned to vary the discharge area of the fan nozzle duct to adjust the thrust of the turbofan engine.
Known thrust reverser assemblies are generally subjected to operational detriments such as, extreme temperatures and general mechanical wear. Over time, depending on the use of the thrust reverser assembly and the duration and strength of such detriments, known thrust reverser assembly components may be subjected to stresses that cause fatigue cracking and/or failure, which may eventually cause suboptimal performance of the thrust reverser assembly.
An example of such thrust reverser assemblies are shown in U.S. Pat. No. 5,778,659 (“the '659” patent) and U.S. Pat. No. 5,806,302 (“the '302” patent). The '659 patent describes a thrust reverser assembly that includes a thrust reverser, an exhaust nozzle, a dedicated thrust reverser actuation system for translating the thrust reverser, and a dedicated sleeve actuation system for translating the exhaust nozzle. The '302 patent describes a thrust reverser that includes a first actuator that is coupled to a thrust reverser cowl, and a second actuator that is coupled to an exhaust nozzle. Each thrust reverser assembly described in the '659 patent and the '302 patent includes dedicated actuators for each translating cowl that may increase the cost, weight, and/or maintenance of the thrust reverser assembly.
U.S. Pat. No. 4,922,713 (“the '713” patent) describes a thrust reverser that includes a first movable cowl, a second movable cowl, and an actuation system that is operatively interposed between a stationary cowl and the second cowl for moving the first and second cowls. In addition, the thrust reverser assembly shown in the '713 patent includes a first locking system for locking the first cowl to the stationary cowl, and a second locking system for locking the second cowl to the first cowl. By including the second locking system between the first cowl and the second cowl, the thrust reverser assembly shown in the '713 patent may require flexible hoses and/or electrical cables to bridge a gap defined between the stationary cowl and the first cowl during operation, which undesirably exposes these components to adverse environmental conditions.
Another example of a thrust reverser assembly is shown in U.S. Pat. No. 5,655,360 (“the '360” patent). The '360 patent describes a thrust reverser that includes a forward stationary cowl, an aft translating cowl, and a deflector door that is coupled to the aft cowl and is selectively deployable when the aft cowl moves from a stowed position to a fully deployed position. The deflector door is positioned within a slot that is defined by a core cowl and is sized to enable the deflector door to translate an axial distance within the slot before being deployed.